/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 3
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "quakedef.h"

char *pr_opnames[] =
{
	"DONE",			"MUL_F",		"MUL_V",		"MUL_FV",		"MUL_VF",		"DIV_F",
	"ADD_F",		"ADD_V",		"SUB_F",		"SUB_V",		"EQ_F",			"EQ_V",
	"EQ_S",			"EQ_E",			"EQ_FNC",		"NE_F",			"NE_V",			"NE_S",
	"NE_E",			"NE_FNC",		"LE",			"GE",			"LT",			"GT",
	"LOAD_F",		"LOAD_V",		"LOAD_S",		"LOAD_ENT",		"LOAD_FLD",		"LOAD_FNC",
	"ADDRESS",		"STORE_F",		"STORE_V",		"STORE_S",		"STORE_ENT",	"STORE_FLD",
	"STORE_FNC",	"STOREP_F",		"STOREP_V",		"STOREP_S",		"STOREP_ENT",	"STOREP_FLD",
	"STOREP_FNC",	"RETURN",		"NOT_F",		"NOT_V",		"NOT_S",		"NOT_ENT",
	"NOT_FNC",		"IF",			"IFNOT",		"CALL0",		"CALL1",		"CALL2",
	"CALL3",		"CALL4",		"CALL5",		"CALL6",		"CALL7",		"CALL8",
	"STATE",		"GOTO",			"AND",			"OR",			"BITAND",		"BITOR"
};

char *PR_GlobalString (int ofs);
char *PR_GlobalStringNoContents (int ofs);


//=============================================================================

/*
=================
PR_PrintStatement
=================
*/
void PR_PrintStatement (dstatement_t *s)
{
	int		i;

	if ((unsigned) s->op < sizeof (pr_opnames) / sizeof (pr_opnames[0]))
	{
		Con_Printf (PRINT_DEFAULT, "%s ",  pr_opnames[s->op]);
		i = strlen (pr_opnames[s->op]);

		for (; i < 10; i++)
			Con_Printf (PRINT_DEFAULT, " ");
	}

	if (s->op == OP_IF || s->op == OP_IFNOT)
		Con_Printf (PRINT_DEFAULT, "%sbranch %i", PR_GlobalString (s->a), s->b);
	else if (s->op == OP_GOTO)
		Con_Printf (PRINT_DEFAULT, "branch %i", s->a);
	else if ((unsigned) (s->op - OP_STORE_F) < 6)
	{
		Con_Printf (PRINT_DEFAULT, "%s", PR_GlobalString (s->a));
		Con_Printf (PRINT_DEFAULT, "%s", PR_GlobalStringNoContents (s->b));
	}
	else
	{
		if (s->a) Con_Printf (PRINT_DEFAULT, "%s", PR_GlobalString (s->a));
		if (s->b) Con_Printf (PRINT_DEFAULT, "%s", PR_GlobalString (s->b));
		if (s->c) Con_Printf (PRINT_DEFAULT, "%s", PR_GlobalStringNoContents (s->c));
	}

	Con_Printf (PRINT_DEFAULT, "\n");
}

/*
============
PR_StackTrace
============
*/
void PR_StackTrace (pr_context_t *context)
{
	dfunction_t	*f;
	int			i;

	if (context->stackdepth == 0)
	{
		Con_Printf (PRINT_DEFAULT, "<NO STACK>\n");
		return;
	}

	context->stack[context->stackdepth].f = context->xfunction;

	for (i = context->stackdepth; i >= 0; i--)
	{
		f = context->stack[i].f;

		if (!f)
			Con_Printf (PRINT_DEFAULT, "<NO FUNCTION>\n");
		else Con_Printf (PRINT_DEFAULT, "%12s : %s\n", PR_DecodeString (f->s_file), PR_DecodeString (f->s_name));
	}
}


/*
============
PR_Profile_f

============
*/
void PR_Profile_f (void)
{
	dfunction_t	*f, *best;
	int			max;
	int			num;
	int			i;

	num = 0;

	do
	{
		max = 0;
		best = NULL;

		for (i = 0; i < progs->numfunctions; i++)
		{
			f = &pr_env.functions[i];

			if (f->profile > max)
			{
				max = f->profile;
				best = f;
			}
		}

		if (best)
		{
			if (num < 10)
				Con_Printf (PRINT_DEFAULT, "%7i %s\n", best->profile, PR_DecodeString (best->s_name));

			num++;
			best->profile = 0;
		}
	} while (best);
}


/*
============
PR_RunError

Aborts the currently executing function
============
*/
void PR_RunError (pr_context_t *context, char *error, ...)
{
	va_list		argptr;
	char		string[1024];

	va_start (argptr, error);
	vsprintf (string, error, argptr);
	va_end (argptr);

	PR_PrintStatement (pr_env.statements + context->xstatement);
	PR_StackTrace (context);
	Con_Printf (PRINT_DEFAULT, "%s\n", string);

	context->stackdepth = 0;		// dump the stack so host_error can shutdown functions

	Host_Error ("Program error");
}

/*
============================================================================
PR_ExecuteProgram

The interpretation main loop
============================================================================
*/

/*
====================
PR_EnterFunction

Returns the new program statement counter
====================
*/
int PR_EnterFunction (pr_context_t *context, dfunction_t *f)
{
	int		i, j, c, o;
	int		*locals = f->locals ? (int *) qScratch->FastAlloc (f->locals * sizeof (int)) : NULL;

	// push a new stack
	context->stack[context->stackdepth].s = context->xstatement;
	context->stack[context->stackdepth].f = context->xfunction;
	context->stack[context->stackdepth].locals = locals;
	context->stackdepth++;

	if (context->stackdepth >= MAX_STACK_DEPTH)
		PR_RunError (context, "stack overflow");

	// save off any locals that the new function steps on
	if ((c = f->locals) != 0)
	{
		for (i = 0; i < c; i++)
			locals[i] = ((int *) pr_globals)[f->parm_start + i];
	}

	// copy parameters
	o = f->parm_start;

	for (i = 0; i < f->numparms; i++)
	{
		for (j = 0; j < f->parm_size[i]; j++)
		{
			((int *) pr_globals)[o] = ((int *) pr_globals)[OFS_PARM0 + i * 3 + j];
			o++;
		}
	}

	context->xfunction = f;

	return f->first_statement - 1;	// offset the s++
}


/*
====================
PR_LeaveFunction
====================
*/
int PR_LeaveFunction (pr_context_t *context)
{
	int	i, c;

	if (context->stackdepth <= 0)
	{
		Sys_Error ("prog stack underflow");
		return -1;
	}

	// restore locals from the stack
	c = context->xfunction->locals;

	// up stack
	context->stackdepth--;

	// if there were no locals (context->stack[context->stackdepth].locals is NULL) this loop is safe as it won't even run
	for (i = 0; i < c; i++)
		((int *) pr_globals)[context->xfunction->parm_start + i] = context->stack[context->stackdepth].locals[i];

	context->xfunction = context->stack[context->stackdepth].f;

	return context->stack[context->stackdepth].s;
}


/*
====================
PR_ExecuteProgram
====================
*/
void PR_ExecuteProgram (pr_context_t *context, func_t fnum)
{
	eval_t	*a, *b, *c;
	int			s;
	dstatement_t	*st;
	dfunction_t	*f, *newf;
	int		runaway;
	int		i;
	edict_t	*ed;
	int		exitdepth;
	eval_t	*ptr;

	if (!fnum || fnum >= progs->numfunctions)
	{
		if (pr_env.globalStruct->self)
			ED_Print (PR_ProgToEdict (pr_env.globalStruct->self));

		Host_Error ("PR_ExecuteProgram: NULL function");
	}

	f = &pr_env.functions[fnum];

	runaway = 100000;
	context->trace = FALSE;

	// make a stack frame (is this always 0???)
	exitdepth = context->stackdepth;

	s = PR_EnterFunction (context, f);

	while (1)
	{
		s++;	// next statement

		st = &pr_env.statements[s];
		a = (eval_t *) &pr_globals[st->a];
		b = (eval_t *) &pr_globals[st->b];
		c = (eval_t *) &pr_globals[st->c];

		if (!--runaway)
			PR_RunError (context, "runaway loop error");

		context->xfunction->profile++;
		context->xstatement = s;

		if (context->trace)
			PR_PrintStatement (st);

		switch (st->op)
		{
		case OP_ADD_F:
			c->_float = a->_float + b->_float;
			break;

		case OP_ADD_V:
			c->vector[0] = a->vector[0] + b->vector[0];
			c->vector[1] = a->vector[1] + b->vector[1];
			c->vector[2] = a->vector[2] + b->vector[2];
			break;

		case OP_SUB_F:
			c->_float = a->_float - b->_float;
			break;

		case OP_SUB_V:
			c->vector[0] = a->vector[0] - b->vector[0];
			c->vector[1] = a->vector[1] - b->vector[1];
			c->vector[2] = a->vector[2] - b->vector[2];
			break;

		case OP_MUL_F:
			c->_float = a->_float * b->_float;
			break;

		case OP_MUL_V:
			c->_float = a->vector[0] * b->vector[0] + a->vector[1] * b->vector[1] + a->vector[2] * b->vector[2];
			break;

		case OP_MUL_FV:
			c->vector[0] = a->_float * b->vector[0];
			c->vector[1] = a->_float * b->vector[1];
			c->vector[2] = a->_float * b->vector[2];
			break;

		case OP_MUL_VF:
			c->vector[0] = b->_float * a->vector[0];
			c->vector[1] = b->_float * a->vector[1];
			c->vector[2] = b->_float * a->vector[2];
			break;

		case OP_DIV_F:
			c->_float = a->_float / b->_float;
			break;

		case OP_BITAND:
			c->_float = (int) a->_float & (int) b->_float;
			break;

		case OP_BITOR:
			c->_float = (int) a->_float | (int) b->_float;
			break;

		case OP_GE:
			c->_float = a->_float >= b->_float;
			break;

		case OP_LE:
			c->_float = a->_float <= b->_float;
			break;

		case OP_GT:
			c->_float = a->_float > b->_float;
			break;

		case OP_LT:
			c->_float = a->_float < b->_float;
			break;

		case OP_AND:
			c->_float = a->_float && b->_float;
			break;

		case OP_OR:
			c->_float = a->_float || b->_float;
			break;

		case OP_NOT_F:
			c->_float = !a->_float;
			break;

		case OP_NOT_V:
			c->_float = !a->vector[0] && !a->vector[1] && !a->vector[2];
			break;

		case OP_NOT_S:
			c->_float = !a->string || !(PR_DecodeString (a->string))[0];
			break;

		case OP_NOT_FNC:
			c->_float = !a->function;
			break;

		case OP_NOT_ENT:
			c->_float = (PR_ProgToEdict (a->edict) == sv.worldedict);
			break;

		case OP_EQ_F:
			c->_float = a->_float == b->_float;
			break;

		case OP_EQ_V:
			c->_float = (a->vector[0] == b->vector[0]) && (a->vector[1] == b->vector[1]) && (a->vector[2] == b->vector[2]);
			break;

		case OP_EQ_S:
			c->_float = !strcmp (PR_DecodeString (a->string), PR_DecodeString (b->string));
			break;

		case OP_EQ_E:
			c->_float = a->_int == b->_int;
			break;

		case OP_EQ_FNC:
			c->_float = a->function == b->function;
			break;

		case OP_NE_F:
			c->_float = a->_float != b->_float;
			break;

		case OP_NE_V:
			c->_float = (a->vector[0] != b->vector[0]) || (a->vector[1] != b->vector[1]) || (a->vector[2] != b->vector[2]);
			break;

		case OP_NE_S:
			c->_float = strcmp (PR_DecodeString (a->string), PR_DecodeString (b->string));
			break;

		case OP_NE_E:
			c->_float = a->_int != b->_int;
			break;

		case OP_NE_FNC:
			c->_float = a->function != b->function;
			break;

		case OP_STORE_F:
		case OP_STORE_ENT:
		case OP_STORE_FLD:		// integers
		case OP_STORE_S:
		case OP_STORE_FNC:		// pointers
			b->_int = a->_int;
			break;

		case OP_STORE_V:
			b->vector[0] = a->vector[0];
			b->vector[1] = a->vector[1];
			b->vector[2] = a->vector[2];
			break;

		case OP_STOREP_F:
		case OP_STOREP_ENT:
		case OP_STOREP_FLD:		// integers
		case OP_STOREP_S:
		case OP_STOREP_FNC:		// pointers
			ptr = (eval_t *) ((byte *) sv.worldedict + b->_int);
			ptr->_int = a->_int;
			break;

		case OP_STOREP_V:
			ptr = (eval_t *) ((byte *) sv.worldedict + b->_int);
			ptr->vector[0] = a->vector[0];
			ptr->vector[1] = a->vector[1];
			ptr->vector[2] = a->vector[2];
			break;

		case OP_ADDRESS:
			ed = PR_ProgToEdict (a->edict);

			if (ed == (edict_t *) sv.worldedict && sv.state == ss_active)
				PR_RunError (context, "assignment to world entity");

			c->_int = (byte *) ((int *) &ed->v + b->_int) - (byte *) sv.worldedict;
			break;

		case OP_LOAD_F:
		case OP_LOAD_FLD:
		case OP_LOAD_ENT:
		case OP_LOAD_S:
		case OP_LOAD_FNC:
			ed = PR_ProgToEdict (a->edict);
			a = (eval_t *) ((int *) &ed->v + b->_int);
			c->_int = a->_int;
			break;

		case OP_LOAD_V:
			ed = PR_ProgToEdict (a->edict);
			a = (eval_t *) ((int *) &ed->v + b->_int);
			c->vector[0] = a->vector[0];
			c->vector[1] = a->vector[1];
			c->vector[2] = a->vector[2];
			break;

		case OP_IFNOT:
			if (!a->_int)
				s += st->b - 1;	// offset the s++

			break;

		case OP_IF:
			if (a->_int)
				s += st->b - 1;	// offset the s++

			break;

		case OP_GOTO:
			s += st->a - 1;	// offset the s++
			break;

		case OP_CALL0:
		case OP_CALL1:
		case OP_CALL2:
		case OP_CALL3:
		case OP_CALL4:
		case OP_CALL5:
		case OP_CALL6:
		case OP_CALL7:
		case OP_CALL8:
			context->argc = st->op - OP_CALL0;

			if (!a->function)
				PR_RunError (context, "NULL function");

			newf = &pr_env.functions[a->function];

			if (newf->first_statement < 0)
			{
				// negative statements are built in functions
				i = -newf->first_statement;

				if (i >= pr_numbuiltins)
					PR_RunError (context, "Bad builtin call number");

				pr_builtins[i] (context);
				break;
			}

			s = PR_EnterFunction (context, newf);
			break;

		case OP_DONE:
		case OP_RETURN:
			pr_globals[OFS_RETURN] = pr_globals[st->a];
			pr_globals[OFS_RETURN + 1] = pr_globals[st->a + 1];
			pr_globals[OFS_RETURN + 2] = pr_globals[st->a + 2];

			s = PR_LeaveFunction (context);

			if (context->stackdepth == exitdepth)
				return;		// all done

			break;

		case OP_STATE:
			ed = PR_ProgToEdict (pr_env.globalStruct->self);
			ed->v.nextthink = pr_env.globalStruct->time + 0.1;

			if (a->_float != ed->v.frame)
				ed->v.frame = a->_float;

			ed->v.think = b->function;
			break;

		default:
			PR_RunError (context, "Bad opcode %i", st->op);
		}
	}
}


void PR_RunInteraction (func_t fnum, edict_t *self, edict_t *other, float time)
{
	// this should be the only entry-point for PR_ExecuteProgram
	int mark = qScratch->GetLowMark ();

	// create a new execution context
	pr_context_t context;

	// fill it in and create a stack for it
	memset (&context, 0, sizeof (pr_context_t));
	context.stack = (prstack_t *) qScratch->FastAlloc (MAX_STACK_DEPTH * sizeof (prstack_t));

	// set the time
	pr_env.globalStruct->time = time;

	// update edicts involved in this interaction then call the function
	if (self) pr_env.globalStruct->self = PR_EdictToProg (self);
	if (other) pr_env.globalStruct->other = PR_EdictToProg (other);
	if (fnum) PR_ExecuteProgram (&context, fnum);

	// and free any temp memory used by this execution
	qScratch->FreeToLowMark (mark);
}

